What happens at a mammogram: does it hurt, 2D or 3D, and results

Maybe you're in your forties and nowhere near your first NHS invitation, or it has been a while since your last screen. Or a friend has told you it hurts, and you'd like to know what you're walking into.

Here is what actually happens. A mammogram is a low-dose X-ray of both breasts. A female radiographer positions each breast in turn, presses it firmly for a few seconds, and takes the pictures. The whole appointment takes 20 to 30 minutes, and most women describe it as uncomfortable rather than painful.

If you'd rather skip the reading, you can book your mammogram now, with no referral needed. The wider breast imaging range is on our private mammogram page.

How do I prepare for a mammogram?

You may be asked to leave off deodorant, antiperspirant and talcum powder on the day, because they can show up on the X-ray image and affect the reading. Wear separates rather than a dress, so you only need to undress from the waist up.

If you have breast implants, or you're pregnant or breastfeeding, tell us when you book so the right scan is arranged. With implants the technique is slightly modified, and the radiographer will be ready for it.

What happens during the scan?

A female radiographer positions each breast in turn between two plates on the mammography machine. The plates press the breast flat for a few seconds, which spreads the tissue out and gives a clear image with a lower X-ray dose. A standard mammogram takes two pictures of each breast, one from above and one from the side.

Your visit, stage by stage

Does a mammogram hurt?

For most women, no more than briefly. Cancer Research UK describes firm pressure for a few moments that is likely to be uncomfortable. Some women do find it painful, but it is over quickly, and the radiographer can stop at any time to make you more comfortable.

The pressure is there for a reason. Flattening the breast stops tissue overlapping on the image and keeps the dose low, so a few seconds of squeeze buys a clearer picture. If your breasts are tender, or you've found mammograms hard before, mention it when you arrive.

2D or 3D mammogram: what's the difference?

A standard digital mammogram is a 2D picture: two X-rays of each breast, from above and from the side. It is the test the NHS Breast Screening Programme uses, and it is our standard mammogram of both breasts.

A 3D mammogram, or digital breast tomosynthesis, takes more X-rays than a standard mammogram. The X-ray tube moves over the breast taking a series of low-dose pictures from different angles, and a computer builds them into thin slices the radiologist can scroll through. Cancer Research UK notes it is available in some hospitals. We can arrange 3D mammography at our partner imaging centre; ask about the price when booking.

The advantage is that overlapping tissue is less likely to hide a small change, which matters most in dense breasts. UK research, including the TOMMY trial within the NHS programme, has compared the two. If you've been told your breasts are dense, our guide to mammogram or breast ultrasound explains the density grades and when ultrasound helps.

When will I get my results, and what do they mean?

A consultant radiologist reads your images and sends a written report within 3 working days. On the NHS programme, results arrive by letter, usually within 2 weeks.

Most reports are clear. If something needs a closer look, you'll be asked back for more imaging. Cancer Research UK puts that at around 4 in 100 women screened, and many of them turn out not to have cancer. A breast ultrasound, £450, can assess dense tissue or a specific area in more detail, and further investigation is arranged for you. If you'd like a doctor involved from the start, the breast screening bundle combines a GP consultation, a physical examination and a mammogram, from £449.

Where is the mammogram carried out?

The scan takes place at a specialist partner imaging centre near the clinic, and we coordinate the details of your appointment there. Doctor consultations and results reviews happen here at 117a Harley Street, seven days a week.

How does this compare with NHS breast screening?

The NHS Breast Screening Programme invites women for a mammogram every 3 years from age 50 to 70. If you're under 50, or between NHS rounds, you won't have an NHS appointment due. Private screening mammograms are normally offered from age 40 and aren't tied to the NHS interval, so some women book one between rounds. If your family history puts you at higher risk, your doctor can advise on when to start.

Screening is for breasts that feel normal. If you notice a new lump or a change in shape, skin or nipple, book a breast lump assessment so a doctor can examine you and choose the scan that fits. The NHS programme and a private mammogram can sit side by side, and our sister clinic, Health Screening Clinic, explains how private breast screening fits around the NHS interval.